The disclosed embodiments relate to wireless systems and networks.
Cellular mobile telephony provides voice and data links between users of mobile devices and fixed devices on a network. It gives users mobility without regard to how they are actually connected to the network. This is done by providing access points or base station units (BSU) that can hand off the connections of mobile devices without interruption of the service. 2G (second generation) digital mobile phone service and AMPS (analog mobile phone service) are examples of such telephone networks.
Many limitations exist with such telephony networks. For example, while cellular mobile telephony networks generally provide service over large areas, such networks have limited capacity for the number of user devices that can be connected within the area covered by each BSU.
The bandwidth provided to users of this service is generally considered low bandwidth or “narrow-band access.” Thus, large data applications, such as transferring of large data files, cannot be effectively performed using such networks.
Providers of this service must acquire rights to use licensed radio spectra, often at high investment costs. Thus, employing such networks can be quite expensive for many applications or users.
This type of service is often unavailable or unreliable in certain areas, such as office buildings, convention centers, and train stations, due to physical properties of these areas and/or due to the density of users seeking access to the service.
The Personal Communications Network (“PCN”) provides similar features to users of mobile devices, including voice and data links to a network, while providing mobility. PCN has a user model similar to that for cellular mobile telephony, so user behavior for one can be carried over to the other. PCN does not have some of the same limitations as cellular telephony. It offers wider bandwidth, or “broadband access,” and can provide greater availability with higher reliability in those particular areas that cellular telephony cannot. The RF spectra used by PCN is unlicensed, and no special access rights are required.
PCN uses wireless networking technology, including IEEE 802.11, which use direct-sequence spread spectrum, and Bluetooth, which uses frequency-hopping spread spectrum. Importantly, however, the Bluetooth wireless standard does not support movement from one area of coverage or “cell” to another.
Currently, the most well-known attempt to provide features that PCN offers in a mobile environment is referred to as 3G-(third generation) wireless. 3G-wireless, however, is constrained by factors that do not constrain PCN implementations. These include heavy investment for the acquisition of spectrum usage rights.
The above wireless technologies require knowledge of which BSUs in a network have coverage overlap with other, neighboring BSUs within the network. Such overlap is a prerequisite for BSU to BSU handoff occurring without links getting dropped. Each BSU is typically given the knowledge of BSUs to which they can hand off. One example of this is the GSM system, in which each BSU is under the control of a BSU controller. See, “Mobile Communications”; Jochen Schiller, pp. 84-112 (Addison-Wesley, 2000). In the GSM system, the BSU controllers and the devices that coordinate them (mobile services switching center) are what decide when and where to hand off. A network can have a potentially large number of BSUs, so it can require significant time and effort to inform each BSU about which other BSUs can receive handoffs from it.
Overall, there is a need for a wireless networking system that solves the above problems while supplying the above benefits, as well as providing other advantages.
In the drawings, the same reference numbers identify identical or substantially similar elements or acts. To easily identify the discussion of any particular element or act, the most significant digit or digits in a reference number refer to the Figure number in which that element is first introduced (e.g., element 204 is first introduced and discussed with respect to FIG. 2).
Note: the headings provided herein are for convenience and do not necessarily affect the scope or interpretation of the invention.